Runtime APIs: Quick Reference

This page summarizes the main resources for using the gRPC APIs to interact with the automatic speech recognition (ASR), natural language understanding (NLU), Dialog, and text-to-speech (TTS) runtime services.

API versions and proto files

Service	API	Current version	Proto files	Documentation
ASRaaS	Recognizer	v1	Download	gRPC setup
	Training		Download
NLUaaS	Runtime	v1	Download	gRPC setup
	Wordset		Download
DLGaaS	DialogService	v1	Download	gRPC setup
TTSaaS	Synthesizer and Storage	v1	Download	gRPC setup

gRPC-web support

This table lists the Mix runtime services that are gRPC-Web compliant.

Service	gRPC-Web
ASRaaS	✓
NLUaaS	✓
DLGaaS
TTSaaS	✓

URLs to runtime services

Service	Production URLs1
ASRaaS	asr.api.nuance.co.uk
NLUaaS	nlu.api.nuance.co.uk
DLGaaS	dlg.api.nuance.co.uk
TTSaaS	tts.api.nuance.co.uk
Event logs	log.api.nuance.co.uk

1. For v1 APIs

Authorization URL

Server	URL
Nuance OAuth server	auth.crt.nuance.co.uk

See Authorize your client application for more information.

Authorization scopes

Service	Scopes
ASRaaS	asr: Provides access to the ASRaaS runtime API and resources asr.wordset: Allows client applications to upload ASR wordsets
NLUaaS	nlu: Provides access to the NLUaaS runtime API and resources nlu.wordset: Allows client applications to upload NLU wordsets
DLGaaS	dlg: Provides access to the DLGaaS runtime API and resources
TTSaaS	tts: Provides access to the TTSaaS runtime API and resources
Event logs	log: Provides access to event logs

See Authorize your client application for more information.

Access token lifetime

The access token expires after 15 minutes so must be regenerated frequently.

URN format

Mix.asr DLM, Mix.nlu model, and Mix.dialog resource URNs

urn:nuance-mix:tag:model/context_tag/service(?=language=language)

Where:

• context_tag is the Context Tag specified when creating an application configuration, for example, A93_C1 or coffee_app
• service is one of the following: mix.asr, mix.nlu, or mix.dialog
• language is the Locale of the application configuration. For URNs, this is the 6-letter language code as documented on the Languages page; for example, eng-USA. This applies to Mix.asr and Mix.nlu only

For example, to load the resource for the American English coffee_app application configuration, specify the URN as follows:

Service	URN
Mix.asr	urn:nuance-mix:tag:model/coffee_app/mix.asr?=language=eng-USA
Mix.nlu	urn:nuance-mix:tag:model/coffee_app/mix.nlu?=language=eng-USA
Mix.dialog	urn:nuance-mix:tag:model/coffee_app/mix.dialog

The legacy form of the URN is supported but deprecated.

ASR and NLU wordset URNs

• Application-level wordset: urn:nuance-mix:tag:wordset:lang/context_tag/resourceName/language/service
• User-level wordset: urn:nuance-mix:tag:wordset:lang/context_tag/resourceName/lang/service?=user_id=userId

Where:

• context_tag is the context tag name for this wordset. When you create the wordset, you can provide any context tag name. This name does not have to match the context tag of the companion Mix.asr DLM or Mix.nlu model.
• resourceName is the name of the wordset
• service is one of mix.asr or mix.nlu
• language is the locale of the wordset. For URNs, this is the 6-letter language code as documented on the Languages page; for example, eng-USA.
• userID is the unique identifier for the user

For example, to upload the Mix.asr cities_wordset application-level wordset, specify the URN as follows:

urn:nuance-mix:tag:wordset:lang/names-places/cities_wordset/eng-USA/mix.asr